1. Field of the Invention
The invention relates in general to an optical disk drive, and more particularly to an electrostatic discharge protection device for eliminating static electricity from users so as not to harm precision electrical components in an optical disk drive.
2. Description of the Related Art
In the process of operating an optical disk drive having precision electrical components, users have to contact the optical disk drive. Thus, the static electricity form the users accumulates in conductors or rushes everywhere through the conductors in the optical disk drive. Once the static electricity is transmitted to the precision electrical components, the electrical components are destructible easily.
FIG. 1 is a perspectively top view of the inside of a conventional optical disk drive 10. FIG. 2 is a perspectively bottom view of the inside of the conventional optical disk drive 10. A metallic case 11 has a hollow space, and two fixing guides 111 made of plastic material are disposed at two sides of the case 11 respectively. A metallic rail 112 is slidably disposed in each fixing guide 111. One end of the rail 112 is obstructed by an obstructive lump 113 of the case 11, and the other end of the rail 112 supports two sliding sticks 121 of a tray 12 at two sides. A hook 114 is disposed in one of the rail 112 for blocking a blocking lump 122 located at the rear end of the tray 12 and restricting the distance that the tray 12 jutting out of the case 11. Thus, the tray 12, comprised of plastic, could slide inwards and outwards the case 11 and jut out of the case 11 completely. Moreover, the precision electrical components, such as a spindle motor 13 for rotating a disk or a pickup head 14, are disposed on the tray 12, and the bottom of the tray 12 is covered and protected by a traverse cover 15, which is metal. The front end of the tray 12 connects with a panel 16 having an eject key 17. One end of a flexible flat cable 18 of a print circuit board connects with a main circuit board 19 and is disposed close to the inner surface of the case 11. The other end of the flexible flat cable 18 is movable, connects with the rear end of the tray 12, and is electronically connected to the traverse cover 15. One circuit line of the flexible flat cable 18 and the case 11 are grounded.
When users eject disks by pressing the eject key 17, the static electricity form the users is transmitted to the traverse cover 15 which is metal via the gap between the panel 16 and the eject key 17. Or, when users directly touch the optical disk drive 10, the static electricity is directly transmitted to the traverse cover 15 which is metal, and then the static electricity is eliminated by being transmitted from the flexible flat cable 18 to the case 11. However, though little static electricity can be eliminated, a great quantity of unexpected static electricity may not be eliminated rapidly due to the small size of the flexible flat cable 18. In that situation, the accumulation of static electricity causes destruction. Additionally, if a great quantity of static electricity passes through the flexible flat cable 18 which is used for transmitting signal and data, the signal and data being transmitted at the same time are interfered easily. Consequently, the reliability of the optical disk drive is affected. Furthermore, the hook 114 disposed in the rail 112 which is comprised of thin metal harms the blocking lump 122 which is comprised of plastic when the hook 114 obstructs the blocking lump 122, especially when suffering a great bump. Accordingly, the tray may lock with the rail and thus be unable to eject disks and insert disks normally. Hence, the problems of the electrostatic discharge protection and the breaking of the tray in the conventional optical disk drive need to be solved.